While a lot of areas are off limits now because of the fires, there are some nice areas. I do a lot of riding in the Cleveland national Forest - up Silverado canyon and all the way to Lake Elsinore. If you cross Highway 74 at Elsinore there is a big offroad park and the trail also carries on all the way to Temecula.

I found a book at AAA called Back Country Adventures which gives great detail about many trails in SoCal. it has been a great resource. Another one that can be useful is www.dirtopia.com. This is a Wiki site and while some of the info is a bit sparse it does at least tell you where trails are.

This kinda has to do with wheeling. You know that jeep liberty commerical where it is driving up a paved road and turns on to a dirt road! That was filmed on the 138 going towards silverwood lake. I was with my buddy on the way to do a little off roading up the and was stopped by CHP and he said we had to wait a couple of minutes casue they were fliming and did say what. So we waited and drove thru and of course the road we wanted to take is were they had all the equipment and stuff set up